1. Field of the Invention
The present invention relates to a prophylactic/therapeutic composition for the secondary cataract.
2. Description of Related Art
Since implantation of an intraocular lens was accepted widely in the operation of cataract, fixation of the intraocular lens in the bag has been considered to be the best method in physiological aspect and various operation techniques have been worked out. Among them, a method of the highest authenticity is an envelope technique which incises a part of the anterior capsule, removes the lens cortex and nucleus with aspirating and inserts the intraocular lens from the incised part. In this method, however, the aftercataract, namely the secondary cataract of which opacification of the posterior capsule results from migration and proliferation of the residual lens epithelial cells onto the posterior lens capsule occurs frequently. A physical therapy such as Laser Nd:YAG capsulotomy method, etc. is generally used for treatment of the secondary cataract. However, a risk of causing degeneration of the intraocular lens is pointed out and, therefore, a prophylaxis/therapy for the secondary cataract by medication after implantation of the intraocular lens has been long-awaited.
For the prophylaxis/therapy for the secondary cataract by medication, Arg-Gly-Asp (hereinafter referred to as "RGD", sometimes), a peptide as a minimum unit which is essential to binding between fibronectin and a receptor thereof or an oligomer thereof has been studied. However, it is still insufficient for clinical application as drugs Atarashii Ganka (Journal of the Eye) Vol. 10, (7): 1235-1238 (1993)!.
It is known that Arg-Gly-Asp (RGD) or a compound having an affinous sequence inhibits binding between not only fibronectin but also the other cell adhesive factor and the receptor. Japanese Patent Unexamined Publication No. 316193/1995 discloses a method of synthesizing a cyclic peptide derivative represented by cyclo(-Arg-MeGly-Asp-R)b (SEQ ID NO. 4) (`b` represents an integer of not less than 1) as the above compound or use thereof, R represents an amino acid residue or peptide residue, and Japanese Patent Unexamined Publication No. 3190/1996 (U.S. Pat. No. 5,183,804) discloses a method of synthesizing a polypeptide represented by (Tyr-Ile-Gly-Ser-Arg)c (SEQ ID NO:3) (`c` represents an integer of 1 to 20) as the above compound or use thereof, but use for the secondary cataract is not known yet.